With more than 750 million users worldwide, Facebook is the world's most popular social network. But a recent study appears to validate that Google+, which now has 10 million users despite still on a beta and invite-only mode, can be a serious threat to Facebook's supremacy.

Although Facebook is the most popular site in America, a good amount of consumers don't "like" the social networking site, according to the 2010 American Customer Satisfaction Index (ACSI) E-Business Report, produced in partnership with ForeSee Results.

Facebook scored 64 on the ACSI's 100-point scale, which puts its satisfaction even lower than IRS e-filers. This puts Facebook in the bottom 5% of all measured private sector companies and in the same range as airlines and cable companies -- two perennially low-scoring industries with terrible customer satisfaction, according to the study.

Facebook has been criticized for its privacy issues.

Entry of Google+

In late June, Larry Page-run Google launched Google+ and received high marks from those who used it in test mode. Google+ mimics Facebook while adding new features. With Circles, users can organize contacts into groups and are given the option of which Circles of contacts to share a piece of content with, each and every time they post something. Aside from that, new features also include Hangouts + Huddle, which allows users to engage for free video chats, and Picasa's photo service directly integrated in the site.

Since Google+'s launch, Facebook has announced a partnership with Skype, which will now provide Facebook users with free video chat within the social networking site. Skype previously charged fees for its multi-party video calls in the Skype application, and Facebook previously did not have a video calling service.

Microsoft Corp. had a hand in the partnership -- it has a 1.6% stake in Facebook and it recently signed a deal to buy Skype for $8.5 billion. Microsoft is at loggerheads with Google, as the Bill Gates-founded firm's browser Internet Explorer directly competes with Google's Chrome, its Bing search engine is trailing Google, and its Windows operating system, although leading the desktops and laptops market, is way behind Google's Android OS in smartphones.

Wikipedia Leads Pack

"Facebook is a phenomenal success, so we were not expecting to see it score so poorly with consumers," said Larry Freed, president and CEO of ForeSee Results. "At the same time, our research shows that privacy concerns, frequent changes to the website, and commercialization and advertising adversely affect the consumer experience. Compare that to Wikipedia, which is a non-profit that has had the same user interface for years, and it's clear that while innovation is critical, sometimes consumers prefer evolution to revolution."

Social media websites are measured for the first time by ACSI, and the category includes Facebook, MySpace, Wikipedia and YouTube. The survey was conducted before Google+ was launched in a limited beta test about two weeks ago, so it was not included in the study. Twitter was not included in the social media category because a disproportionate number of users access Twitter through third party applications other than the website Twitter.com. Wikipedia leads the category at 77, followed by YouTube at 73, Facebook at 64 and MySpace at 63.

"Social media has become too big to ignore, so we added it to our list of e-business measures," said Claes Fornell, ACSI founder and professor of business at the University of Michigan. "We are quite surprised to find that satisfaction with the category defies its popularity."

Google's Loyal Following

According to the study, Google plunges 7% but continues to lead the portals and search engines industry with a score of 80. It is also the first time that Google cedes its top spot, as the "all others" category of search engine competitors jumps 5% to 82. Microsoft's Bing search engine makes a strong first showing with a score of 77, trailed by Yahoo! (76), AOL (74), and Ask.com (73).

"Google may be suffering from trying to be too many things to too many people, but it still has the most loyal following with 80% of its users citing google as their primary search engine," said Freed. "That said, Bing's first measure is impressive and could put some pressure on Google. The new search engine is already making gains in market share and using clever marketing and advertising to distinguish itself from the market leader."

Google+ Serious Competition

As to Google+ vs. Facebook, its dominance could change quickly if it doesn't improve its customer satisfaction, said Freed.
"If Google can carry over their customer-centric ethos to Google+, Facebook could have serious competition that has the potential to very quickly erode its market share," Freed wrote in a draft of the report sent to IDG News Service, according to PC World.

Freed, PC World said, noted that Facebook increased its customer satisfaction score from 64 last year to 66 this year -- out of a possible 100 -- a sign the company "may be moving in the right direction, albeit very slowly."

"Facebook is clearly king right now, but if anyone can knock it off its throne, it would be Google," Freed wrote, according to PC World.